Family visitor visa extension

My mom was granted family visitor visa from India for 6 months on 20 may 2014 and visa will expire 20 November 2014. She is planning to come to uk on 9 th november.There may be a graduation ceremony on 21st November if I passed my exams the result will be available only on 14 th november.she very much wants to attend the ceremony before returning if possible.can she extend her stay by 2 days .if so how. she definitely doesn't want to stay longer than nov 22 anyway as she has other commitments back home.


Please advise.